Sealed edge process

ABSTRACT

Edge-sealing process to produce a textile product which is automatically sealed on at least three edges with a plastic film material to eliminate the sewing of a hem.

[50] Field of 156/166, 259, 263, 269, 271, 324, 479, 511, 515, 516, 519,

Gaffney;

Norman E. Klein, lnman, both of S.C. [21] Appl. No. 834,943

[56] References Cited UNITED STATES PATENTS 2,749,817 6/1956 Piazze etal...................

[22] Filed June 20, 1969 [45] Patented Sept. 21, 1971 [73] Assignee 156/271 X 156/271 X 156/517X Deering Milliken Research Corporation p 'ga 3,307,995 3/1967 Martin..........

3,383,268 5/1968 Wethington... 3,385,747 5/1968 Klein et Primary ExaminerBenjamin A. Borchelt Assistant Examiner.lames M. Hanley [54] SEALED EDGE PROCESS 2 Claims, 4 Drawing Figs.

AttorneysNorman C. Armitage and H. William Petry 7 l 5 ABSTRACT: Edge-sealing process to produce a textile [51] Int. B32!) 31/20, product which is automatically sealed on at least three edges B 2b 31/ with a plastic film material to eliminate the sewing of a hem.

PATENTED sP2 1 I97! 3 s07 538 SHEET 1 OF 3 INVENTORS QSCAR M. FULLER NORMAN E.KLE|N ATTORNEY PATENTEB SEPZI lsn SHEET 3 OF 3 INVENTORS OSCAR M. FULLER NORMAN E.KLE|N BY ATTORNEY SEALED EDGE PROCESS This invention relates generally to methods and apparatus for forming a plastic-type selvage in a textile material and more particularly to methods and apparatus for continuously forming from a roll of material such items as diapers, handkerchiefs, etc., which are cut from the roll and the cut edges are automatically sealed with a thermoplastic-type selvage to prevent unraveling.

Prior to this invention it was known to heat-seal a strip of thermoplastic material transverse to the longitudinal direction of a roll of fabric and cut such seal substantially in the center thereof to form individual sealed-edge products. An example of such a machine is shown in U.S. Pat. No. 3,385,747 wherein a roll of fabric is sealed in the weft direction. This machine takes single-width fabric with woven selvages in the warp direction and provides a product with only two sealed edges. Economically, it is desirable to take wide widths of fabric and seal longitudinal portions thereof and then sever the sealed portions substantially in the center thereof to provide a plurality of longitudinal extending sealed separated strips of fabric. These portions can then be automatically supplied to a machine which simultaneously transversely seals all the separated strips in the weft direction and then simultaneously severs the separated strips substantially in the center of the transverse seals to provide a plurality of individual textile products with edges sealed to prevent unraveling of the selvages.

Therefore, it is an object of the invention to provide a method and apparatus which automatically provides a plurality of sealed-edge products from a single width of fabric.

Another object of the invention is to provide a method of and apparatus to apply a thermoplastic material in the longitudinal and transverse direction of a fabric to produce a product which has all the edges thereof sealed.

Other objects and advantages will become readily apparent as the specification proceeds to describe the invention in which:

FIG. 1 is a schematic representation of the preferred method and apparatus to produce a sealed-edge product;

FIGS. 2 and 3 show products produced by the apparatus shown in FIGS. 1 and 4;

FIG. 4 shows a modification of the apparatus of FIG. 1.

In the preferred form of the invention sealed-edge fabrics are being produced continuously from a roll of material. A roll of fabric of sufficient width to produce two of a desired product such as diapers, towels, etc., has a strip of thermoplastic film such as polyvinyl chloride, nylon-6 etc., heatsealed thereto in the longitudinal direction of the fabric. Then the fabric is slit in the middle of the seal to provide two lengths of fabric and preferably supplied continuously to a machine which heat-seals another strip of thermoplastic film across the whole width of each the lengths of fabric. As with the abovementioned longitudinal seal, the film material can be polyvinyl chloride, nylon- 6 or any other suitable material. Under certain conditions a thermosetting-film material may be used but, as indicated, it is preferred to use a thermoplastic-film materia]. Each of the lengths of fabric are then cut approximately in the center of the seal across the width thereof to provide a sealed-edge product. Normally the longitudinal direction of the fabric is the warp direction and the width of the roll of fabric is the fill or weft direction.

FIGS. 2 and 3 represent products obtained from the hereindisclosed invention. FIG. 2 shows a product 10 which has all four edges sealed with a thermoplastic seal 11. The product of FIG. 3 is obtained when the roll offabric slit longitudinally has a selvage l2 finished on the loom so it is only necessary to provide thermoplastic seals 11 on three edges thereof.

Looking now to FIG. 1, the machine schematically represented shows an arrangement wherein one of each of the products of FIGS. 2 and 3 are obtained on each cycle of the machine. It is obvious that two products like FIGS. 2 or 3 can be obtained depending on whether none, one or two of the selvages of the roll of fabric 14 are finished or hemmed prior to introduction into the machine.

In FIG. 1 the overall machine to produce the products of FIGS. 2 and 3 is schematically shown. The roll of fabric 14 to be sealed is supported on a dolly 16, the transverse position of which is controlled by a conventional edge-guide device. Briefly, the edge-guide device consists of a sensing element 18 which senses the edge of the fabric 14 and if the edge of the fabric 14 is not properly positioned a signal will be relayed to the control member 20 to move the dolly in one direction or the other. In the preferred form of the invention, the sensing means employed is pneumatic and the dolly 16 is moved back and forth by a hydraulically motivated piston. Such a system is conventional and per se is not part of the invention.

In the preferred form of the invention, the fabric 14 passes under idler rolls 22 and 24 into the nip of feed rolls 26 and 28 from whence it is supplied under dancer roll 30 and idler 32 into the nip of sealing rolls, generally designated 34 and 36. Preferably, the rolls 34 and 36 are driven at a speed slightly faster than the nip rolls 26 and 28 in order to maintain a predetermined tension in the fabric between the two pairs of rolls. Dancer roll 30 automatically controls the speed of roll 26 depending on the vertical position of the dancer roll in a manner such as that disclosed in U.S. Pat. No. 3,385,747

As discussed briefly before, it is preferred to provide seals on the fabric made from suitable thermoplastic polymer film such as polyvinyl, chloride, nylon-6 etc. In the use of such films certain variables have to be taken into consideration such as the pressure exerted on film-fabric sandwich in the nip, the temperature of the hot surfaces of the nip, the temperature of the fabric entering the nip, the temperature of the film entering the nip, thickness and construction of the fabric, thickness and constituency of the film, the speed at which the fabric passes through, the tension of the fabric and the tension of the film entering the nip. Also it is felt that the temperature of the film in the hot nip must be at least at the softening point to allow the polymer to flow into the fabric. As an example the softening temperature of a 3.5-mil. thick polyvinyl chlorideplasticized polymer film is about 350 F. To provide the best means to maintain such temperature it is felt that the temperature and speed of the fabric and film coming together at the nip of rolls 34 and 36 should be controlled. If these variables are not controlled, various defects in the seal will occur depending on the type of variance. For example, if the film is not sufficiently warm, the flow into the fabric may be insufficient and poor seal adherence may result. If the fabric temperature is not sufficiently high, or if the hot surfaces of the pressure nip are not at a sufficiently high temperature, the fabric and film will be quenched at some temperature below the soften ing point and again poor seal adherence will result. Conversely, if the fabric temperature exceeds the desired temperature to an extent that the fabric becomes dehydrated discoloration of the fabric can result. The film temperature prior to entering the nip must be such that it does not approach the softening temperature to prevent loss of dimensional stability and consequently the production of irregular seals. Further, the pressure at the nip has to be sufficient to cause the softened film to adequately penetrate the fabric.

It can be readily seen from the above that certain conditions must be met once the fabric and film have been selected. As previously discussed, the fabric 14 is delivered from the nip rolls 26 and 28 to the nip of roll members 34 and 36 at a predetermined tension and speed. Depending on the speed selected, the fabric can be preheated in the area of the longitudinal seal by preheaters 38 above and below the fabric. Preheaters 38, preferably, are infrared lamps which provide radiant energy for preheating of the fabric. schematically shown are pneumatically actuated pistons 40 which are actuated by a fabric temperature-sensing device, not shown, to actuate members 41 to open and close shutters on the preheaters 38 in response to the temperature sensed to control the heat supplied to the fabric. At slow fabric-delivery speeds such as 12-14 yards/minute, preheaters 38 normally would not be actuated since the fabric has sufficient time to be heated by the hot portion of the roll members 34 and 36.

Roll members 34 and 36 consist of rubber-covered carrier rolls 42 and copper-heated rolls 44 to heat-seal the film 46 into the fabric 14. Preferably, the copper rolls are heated by electrical cartridge heaters (not shown). Copper rolls 44 are preferably treated with a releaseagent such as silicone to provide the hot roll surfaces with improved release properties. The number of copper rolls employed is dependent upon the number of longitudinal seals laid upon the fabric. in the preferred embodiment, since it is desired to lay down two seals 49 two pairs of copper rolls 44 are employed. To provide controlled nip pressure to the rolls 42 and 44 yoke members 48 and 50 are pivotally secured at 52 and held in nip forming relationship with the lower rolls by application of pressure from the pneumatically actuated cylinders 54. Semicircular fabric lifter members 56 actuated by pneumatically actuated cylinder 58 are provided to lift the fabric 14 off the lower hot rolls 44 when the upper rolls 42 and 44 have been automatically pivoted away from the lower rolls when the machine is stopped.

The film 46 to be sealed to the fabric is provided in roll form on film carriers 60 mounted on the machine. Preferably the carriers 60 contain more than one film roll 62 so that the application of film to the fabric can be continuous so that one roll of film can be automatically threaded up as another roll is running out. The film 46 is supplied over an adjustably mounted roll 64 onto the hot surface of the upper hot roll 44 prior to entrance into the nip of the rolls 44. The amount of warp of the film 46 around the upper roll 44 is dependent on the amount of preheat necessary for the film to be heated to a molten state without it losing its form or continuity. This amount of wrap is controlled by the position of the roll 64 relative to the peripheral surface of the upper hot roll 44.

As pointed out before, the lower roll member 34 is driven so that the fabric 14 is drawn into the nip of rolls 42 and 44 as the molten film 46 is applied thereto and penetrates the fabric 14 due to the pressure between the upper and lower hot rolls 44. in the preferred form of the invention the fabric from the longitudinal sealing machine is supplied to another mechanism which also places a transverse seal upon the fabric but it is within the scope of the invention to take up the fabric on a suitable take up roll after it has been scaled longitudinally and cut. it has been found that when the fabric is supplied to a transverse sealing mechanism there is sufficient time for the longitudinal seal to set so additional cooling is not necessary since the production rate of the transverse sealing mechanism is comparatively slow. If it is desired to take up the fabric immediately after longitudinally sealing and cutting cooling cans or rolls should be used in order to set the seal before takeup.

As shown in FIG. 1 the fabric 14 with the longitudinal seals 49 thereon passes over a pair of fixed bars 66 and 68 to a pair of score cutters 70 and 72, the cutting pressure of which is controlled by pneumatic pistons 74 and 76. As is well know in the art, score-cutting, a cutting-edge bearing on a hardened surface, 78, has a squeezing-type separation, which when applied to a still plastic seal forces the seal around the severed yarns. The fixed bars 66 and 88 tend to squeeze out the longitudinal seal 48 so that the cutters 70 and 72 do not pick up portions of the still tacky seal. Thusly, it is an advantage to slit the longitudinal seals 49 by score-cutting immediately downstream of the seal application zone because of easy registry of he cutter to the seal and quality of the sealed edge.

The tension is maintained on the fabric 14 after passage through the nip of roll members 34 and 36 by a pair of nip rolls 78 and 80 driven at a speed slightly higher than the speed of the roll members 34 and 36. Nip rolls 78 and 80 and roll members 34 and 36 preferably are driven continuously by the same motor as rolls 34, 36, 78 and 80 and the dancer roll 30 can then be eliminated since the dancer roll 82 which controls the speed of the above-mentioned in a manner similar to that disclosed in U.S. Pat. No. 3,385,747 will than also control the speed of rolls 26 and 28. Dancer roll 82 within a narrow range also acts as an accumulator since the transverse sealing mechanism operates intermittently while the longitudinal sealing portion of the machine operates continuously. The dancer roll 82, when the transverse sealing mechanism is not taking fabric, moves downwardly as the longitudinal sealing portion of the machine continues to supply longitudinally sealed fabric.

From the dancer roll 82 the longitudinally sealed fabric 14 is supplied under an idler roll 84 to the nip of the intermittently driven input rolls 86 and 88 of the transverse sealing mechanism of the machine. The input nip rolls 86 and 88 and the output nip rolls 90 and 92 are driven by pneumatically actuated piston 93 which, when actuated, pulls the chain 94 to the left against the bias of spring 96 to rotate sprocket 98 which in turn through suitable mechanical linkage rotates he bottom rolls 86 and 90 a predetermined distance. The predetermined time of rotation of the rolls 86 and 90 determines the length of fabric between transverse seals and can be adjusted to obtain various length products by adjusting the stroke of the piston 93. Located under the fabric 14 between the input and output rolls is a continuously rotating apron system 100 for reasons hereinafter explained. To prevent the fabric 14 from engaging the upper surface of the apron system 100 when the fabric 14 is held between the nips of the input and output rolls the nip of the output rolls 90 and 92 is located slightly higher than the nip of the input rolls 86 and 88. To provide tension in the fabric between the input and output rolls the output rolls 90 and 92 are driven at a speed greater than the input rolls 86 and 88. This differential speed between the rolls also tends to keep wrinkles out of the fabric and expedites the passage of a cut product onto the endless conveyor 102.

Assuming for the sake of discussion, the transverse sealing mechanism has been indexed to feed completed sealed products 10 onto the conveyor 102 and fabric 14 is held between the nip rolls 86 and 88 and 90 and 92. The fabric 14 is now in the position to have a transverse seal placed thereon. When the fabric 14 has been moved to the position shown or just before the fabric reaches this position the piston 104 is actuated to advance a strip of film material from the roll of film 106 on the film-feeding mechanism generally designated 108. The film feed and upper platen assembly 109 are identical to and operate in the same manner as that shown in U.S. Pat. No. 3,385,747 to place the strip of advanced film onto the fabric and heat-seal same thereto. in other words the upper platen 110 is actuated to a downward position onto the film material and fabric and cooperates with the lower platen 112 to heatseal the film to the fabric. Then the piston 104 is actuated in the opposite direction to pivot the film-feed mechanism back to its original position and the upper platen is lifted up off the newly formed sealed fabric portion. It should be noted at this point that upper platen 110 is fixed relative to lower platen 112 and that upper blade 116 is fixed relative to the lower blade 118 so that when the platen-support member 120 is pivoted the platens and blades move together. When the upper platen 110 is retracted the piston 122 is actuated to pivot the platen-support member 120 to move the platens and blades counterclockwise to a position where the knife blades 116 and 118 are over and under the previously formed transverse seal. Then the piston 124 is actuated to bring the upper knife blade 116 downwardly to cooperate with the lower knife blade 118 to sever the fabric 14 substantially in the center of the seal. Then the upper blade 118 is retracted and the platensupport member 120 pivoted back by the piston 122 to the position shown in FIG. 1. When the platen-support member 120 has returned or almost returned to the position shown in FIG. 1 he piston 93 is actuated to rotate the rolls 86 and 88 and rolls 90 and 92. Actuation of output rolls 90 and 92 causes the completed sealed-edge products 10 to be delivered to the endless conveyor which deposits them in a suitable container. As discussed before, apron system 100 is driven continuously but does not contact the fabric 14 in the position shown in FIG. 1 but the fabric 14, when severed by the blades will, tend to drop onto the aprons. Then when the rolls 86 and 88 are actuated the aprons will guide the fabric 14 into the nip or rolls 90 and 92 for the next operation. Then the hereindescribed operation is successively repeated to provide a plurality of sealed-edge products.

FIG. 4 is a modification of that shown in FIG. 1 and is capable of producing the products shown in FIGS. 2 and 3. Components indicated by a reference number in FIG. 1 will have the same reference number in FIG. 4 if the component is the same. The basic difference between the apparatus of FIG. 4 from that shown in FIG. 1 is that the continuously operating transverse sealing mechanism l26 is substituted for the intermittently operating mechanism of FIG. 1. The transverse sealing mechanism 126 is identical to that disclosed in US. Pat. No. 3,385,747 except it provides more than one textile product with a transverse seal thereon at the same time. Also, in this form of the invention the input nip rolls 86 and 88 will preferably operate continuously to supply fabric to the mechanism 126. V

The hereindisclosed method and apparatus automatically takes a multiple-width fabric and provides simultaneously a plurality of textile products which has the edges sealed to prevent unraveling.

Although the preferred embodiments of the invention have been described in detail, it is contemplated that many changes may be made without departing from the scope or spirit of the invention and it is desired to be limited only by the claims.

1. Method to simultaneously produce a plurality of sealededge products from a supply of textile fabric comprising the steps of: providing a supply of textile fabric, continuously applying a plastic seal longitudinally of said textile fabric, automatically cutting said textile fabric through said plastic seal to form at least two textile fabric portions, supplying said textile fabric portions to a second sealing zone, applying a plastic seal to said textile fabric portions transversely thereof, and cutting said textile fabric portions through said transverse plastic seal to provide a plurality of sealed-edge textile products.

2. The method of claim 1 wherein said plastic seals are heatsealed to said textile fabric. 

2. The method of claim 1 wherein said plastic seals are heat-sealed to said textile fabric. 